Internal-combustion engine.



I F. J KHVIBALL INTERNAL COMBUSTION IGINE.

APPLICATION FILED JUNE 27.1914.

Patented Oct. 10, 1916.

4 SHEETS-SHEET I.

F. L'KIMBALL. INTERNAL COMBUS I N ENGINE. APPLICATION FILED JUNE 2?, I914.

4 SHEETS-SHEET 2.

. I l ate rdf 0ct.10,1916,

F. J} KIMBALL. INTERNAL COMBUSTION ENGINE. APPLICATION FILED JUNE 27.1914 i 1 20 858 Patented Oct.10,-1916 4 SHEETS-SHEET 3.

F. l, KIMBALL. INTERNAL 'COMBUSTION ENGINE. APPLICATl O'N men JUNE 21. 19:4.

4 SHEETS-SHEET 4.

2%? lmuu L @20 .11 u ii i I Patented 0t.'10,-1916,

ournnisrarnsraraiar FRANK U. KID/[BALL QF LOS .ANGELES, CALIFORNIA, ASSIGN'OR TO FRANK J. KIMBALL antenna comrm, or Los ANGELES, camromvm, A CORPORATION or oamromvm.

rn-rnnnat-coMBUs'r-ion ENGINE.

To all whom it may concern: v

"Be it known that I, l nan'n J. KIMBALL, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful Internal-Combustion Engins, of which the following is a specification. This invention relates to. internal combustion engines of the type in which a charge of mixed fuel and air is compressed after it enters the cylinder, and the main object of the invention is to increase the expension, in the expansion strokeoi': the engine, relatively to the compression in the compression stroke, so that the pressure at which the gases are discharged from the engine is reduced to a minimum, with resultlng increase in efiiciency of the engine.

Another object of the invention is to provide for utilization of low grade or heavy fuel, by forming a combustible mixture of such'fuel with air, under sufficiently high pressure and temperature, to maintain the mixture, temporarily, in gaseous condition, then introducing a charge of such mixture into the cylinder of the engine and further compressing the same.

While my invention is applicable to in ternal combustion. engines of any type, usmg charge compression, it 38 particularly applicable to engines of the two-cycle type, .and an important object of the invention,

in connection with such an engine, is to provide for thorough and effective scayengmg of the cylinder. by agpositive sca yenging action.

The accompanying drawings illustrate an embodiment of my invention and referring thereto: Figure 1 is a plan view of the engine. Fig. 2 is a longitudinal section on line 0a w in Fig. 1'. f Fig. 3 is partly broken side elevation'ofthe mixture inlet means for the main cylinder. Fig. 4 is a section on line m -;r* in Fig. 1. 'Fig. .5 is a section on line 12 -03 in Fig; 1. Fig. 6 is a slde elevation partly broken away. Fig. 7 is a partial longitudinal section of a modified form of the. engine.

Referring to the form of the invention shown in Figs. 1 to 5, the engine therein shown is provided with a crank case 1, on which is journaled the engine shaft 2 (see Fig. 1); said crank case also serving as a specification of Letters Patent.

Patented Qchii), 1916.

Application filed June 27, 1914. Serial No. M71570.

support for the cylinder means of thesemain piston 5, Working in cylinder 3, is provided with a flange or enlargement 8, workingin the cylinder i, which is sufficiently larger than the main cyiinder 3 to form an annular lovv pressure cylinder chamber 9 between the wall of cylfinder and the body of piston 5. Pistons and 8 are provided with the usual packin rings 10 and 10. The crank case 1 is provided with a spring controlled inwardly opening inlet valve 6, and a pipe or duct 7 leads from the crank case to a port 16 in the cy inder 3.

The main cylinder .is provided with exhaust port 17 and scavenging inlet port 16, located near the outer end of the cylinder so as to be opened by the piston it approaches the outer end of'its stroke. Cylinder 3 is also provided with an inlet port 12 for mixture of fuel anc air, and for a supply of low ressure air for positive scavenging, said inlet portbeing iocated at the inner or head end of the cylinder, for example, in the head 13 of the cylinder. An inwardly opening puppet valve 14 controls communication between a valve chamber 15 in the head 13, and the interior of the cylinder 3, said valve being normally held closed by a spring 18 whose tension may be adjusted by means 19, so that the valve will open only under a definite excess of pressure in the valve chamber over the pressure in the cylinder. Main cylinder 3 15 also provided 'wltha supplementary exhaust port :20 located in position to belclosed by the piston during the inward sti'iyke thereof, say at about half nected by chain gearing 30 or, otherwise, to-

- the main shaft 2 of theengine, so as to fuel and air supply means comprises a pump intake valve 33 connected by '32 having its pipe 33' with a carbureter 34 or any other means for furnishing fuel and air; the out through a pipe 35, I chamber for cylinder 3. This pump 32 may comprise a cylinder in wh1ch works a piston 29, operated by an eccentric 25 on the carbureter let valve 35 of said pump communicating a mixin chamber 36 and an outlet pipe 31, with t e inlet valve shaft 28 above referred to. The pump 32 is adapted, at each upstroke of its piston, to draw in a charge of air and fuel through 34, and in the next downstroke, to compress this mixture of fuel and air to a. high pressure, say eighty to onehundred pounds per square inch, the-mixture of air and fuel being heated by this compression sufficiently to temporarily hold the fuel in the form of a gas. The outlet pipe 35 for said pump is made of such small diameter that the discharge from the pump -will travel therethrough at high velocity, andwill retain its temperature and state of mixture until it reaches the mixing chamber 36, where it is mixed with a further titypf air, as hereinafter described. The outlet 35 of pipe 35 is normally closed by a pop-"valve'3'i, (Fig. 5) controlled by a spring 38 whichis set to allow the valve to open only at a relatively high pressure, say eighty to one hundred pounds per square inch. The pressure of th1s spring may be adjusted by a. cap 39 hearing thereon and screwing on a support 40. A low pressure air supply pipe 41 also opens into this mixing chamber and in order to insure thorough mixture of the fuel and air, the mixing chamber is preferablyof the circular form shown, with the low pressure air pipe 41 entering the same tangentially, and the out let 35 for the fuel and air pipe 35 extending axially in the chamber 36, so that when the pop-valve 37 is suddenly opened by the pressure of the compressed mixture of fuel and air, this mixture is violently ejected in the orm of a radial sheet or spray, into the tangentially moving current of air in the chamber 36, and is then drawn out through the outlet 31 leading to the valve chamber 315, said outlet being axially arranged, with respect to the chamber '36, so that it is at the center of the vortex setup in the chamber, and therefore at the point of most violent agitation.

Thelow pressure air pipe 41 leads from a storage chamber 43 which communicates with quan- 7 chamber 9, p

opening inlet valve '48, normally held closed by a' spring 49. Valve chamber 47' has an intake 50 for air, controlled by a throttle 51,

which is connected'to a governor 52' by any suitable means,

link connections 52, 53, 54 between throttle for example by lever and.

51 and a shaft 55, and leverjand link conr nections 56, 57, 58, between said shaft and the governor. The the shaft 28 may also, through connections 61 and 62, control a throttle 63 for the carbureter 34.

Any suitable means is provided forgig niting the compressed charge in the main cylinder, for example, means for producing a prgper time.

he operation is as follows: At each stroke of the piston 5 in an inward direction, that is, there is a condition of suction produced in the crank case 1, and the inletx'yalve .6 opens, allowing air to be drawn into the crankcase. During thisinward st-roke,-also, air, is'being compressed inthe low pres sure cylinder chamber 9, say to a pressure of three to five pounds per and is forced'into the storage chamber 43 governor may be driven by above referred to. Governor 52.

toward the head of the Cylinder,

a spark plug 60, and": spark thereat at the square inch,

andthe pipe 41 connected thereto, but is prevented from passing into the cylinder 3 by the valve 14, which at this timeis held closed by the pressure in said cylinder and by its spring 18. In the next succeeding outward stroke of the piston 5, the valve 6 is closed by its spring, and the piston compresses the air in the crunk case until it has nearly reached the end of the 'outstroke, when it opens the ports 16 and 17, allowing air to pass from the crank case through pipe 7,

and port '16 to the cylinder 3, this air being blown through the cylinder so as to effect a preliminary scavenging. -At the moment the pressure in the cylinder 3 falls, by reason of the escape of'gasesl therefrom through the exhaust port .17,

the air inlet valve 14 starts'to open under the pressure of the compressed .air from storage chamber 43, and

such compressed air then passes through said valve and blows through said c vlinder,

scavenging thecylinder with a positive action. While the piston 5 is at the outer portion of its stroke, for example, before it has closed the exhaust port 17, the supplementary exhaust valve 22 is opened by action of eccentric 26, so that fresh air entering-at valve 14 may continue to scavenge the cylinder during the first portion of the instroke, thereby prolonging the period of exhaust and enabling more thorough scavenging. The pump 32 isso timed in its action, relatively to the piston 5, that during'this outer portion of the instroke of the piston said .5 pump will compress a mixture of air and fuel and (rinse-compressed inthe pump32 is sufiiciently rich to preventit' from being pre-:'-

40. maturely ignitedby the heat due to compres-f.

' fuel to a condition of high pressure, and cor respondingly high temperature and will force such compressed hot mixture through the pipe 35 to the popyvalve 37 of the mixing chamber 36, and when 'the pressure reaches a definite predetermined amount, say eighty pounds per square inch, said pop valve will suddenly open allowing the com-v pressed mixture to issue violently into the mixing chamber in'the form t a radial .pray or sheet of mixture, in the path of the. blast of compressed airpassing through. the

mixing chamber from the storage chamber; 43 to the cylinder 3, and as this current ofair is moving vortic ally or in a whirling man ner, at high "velocity, it takes up the rich mixture thus discharged into it and mixes it thoroughly with the low pressure air from pipe 41, the resultant mixture then passing through the duct 31 and valve 14 to cylinder; 3. The pump32 isfofj'relatively small ca-' pacityfcompared to the main-cyl nder 3 and the cylinder, chamber 9,,as it'i's only necessary to compress thereinasmall portion of sathe total-charge, including only sufiicient -fa irtocarry'and vaporizethe liquid fuel. 'By reasen ofj'this small capacity of the said pump, it is possible to compressthe mixture "therein to the stated high'pressure without expending an undue proportion of the work done by the main cylinder. ."Moreover by reason of the relatively small amount 0 air so compressed with the fuehthe mixture of sion in said. pump, butforms'anexplosive mixture when dilut'ed with the fresh air in Y the main cylinder. I preferte so time the operation of the parts. aforesaid-that this mixture entering'the cylinder will reach, the supplementary exhaust port .20 at about the same timethat the piston 5 closes, said port, thereby insuring'a clean full charge in the 1 u compression chamber of cylinder 3, ,Without waste of fuel. The further inward movement of piston'fi then compresses the charge, this compression beginning at the moment the time of full compression, at the inner that the valve 22 closes and continuing until the ignition means 60, with the result that the piston is driven outwardly by the expanend of the stroke, the charge is ignited by sion of the burning gases. ID'uring the ex- 'pansion stroke the supplementary exhaust valve. 22 is held'clo'sed, so that exhaust doesf not begin until thepiston opens the port 1 17 at the end of the stroke.

It will be noted that compression does not begin until the piston has moved. a considerable distance on its instroke, butthat expansion continues during substantially the whole outstroke, so that the efi'ect is to increase the ratio of expansion relatively to 1 80.1 this ratio that the exhaust gases are disthe compressionyand I prefer to so increase charged at substantially atmospheric pressure, thereby eliminating, the waste due to p high terminal pressureat the exhaust. This" gives a high fuel economy and I am also enabled to further increase the fuel economy by increasing, if desired, the compres'-" sion in the cylinder 3', beyond the usual limitations. This effect I secure by decreasing the charge and decreaslng the clearance in greater ratio than the decrease of charge,

so that the combustion chamber is short ened and the'time of exposurepf thehot gases to the metal of thecylindelnis corree spondingly reduced, so that a hi'gh com pression may be used without liahility of premature ignition. The decrease m-hlear-j ance enables the decreased charge tobh'lcompressed to a higher pressure, and the Short 7 ening of the compression stroke enables this higher compression to be effected "without premature ignition; the increaseof heating effect due to greater compression being offset by the decrease in absorption of heat from the Wall of the cylinder. 1

In applying the invention to .direct acting pumps or compressors, where crank case compression is not available, I may, *as shown in Fig. 7, provide a trunk cylinder 64 on the end of the cylinder extension 4,

and serving as a compression cylinder for scavenging a1r, which is d1scharged to the main cylinder through a duct7 as above de- 7 scribed. The piston rod 65 for the pump or compressor passes through a stufiing box in the head of this trunk cylinden; I

\Vhat I claim is:

1. In an. internal combustion engine, a

cylinder having inlet connection for combustible. mixture, andexhaust connections for products ofcombustl'on, means for supplying scavenging air through said inlet connections and for subsequently supplying mixture through'said inlet connections, dur-. ing the inward stroke of the piston, a piston working in said cylinder, means for maintaining the exhaust connections open during apart of the inward stroke of the piston, to permit scavenging, for then closing said ex- 110 said trunk cylinder having an inlet valve 6,

hau st connections to permit compression during the latter part of the inward stroke .of the piston, and for maintaining the ex- -haust connections closed during substantially the full outward stroke of the piston.

2. In an internal combustion engine, the combination of a cylinder, a piston working therein,vsaid cylinder being provided with exhaust and scavenging inlet ports in position to beopened by the piston at the end of its expansion stroke, and being provided with an inlet port for mixture and for scavenging air and with asupplement'ary ex-' haust port in position to remain open dur-- ing a portion of the inward stroke of the piston, means for supplying air through said mixture inlet port during the first part of the compression stroke while the supplementary exhaust port is open, and means for supplying combustible to such air during the latter part of the supply thereof, a valve controlling said supplementary exhaust port and operatedby theengine to open said port during the first portion of the inward stroke of the piston and to close said port during the rest of the inward stroke and during substantially-the full outward stroke of 'the piston.

3. In an internal combustion engine, a cylinder, a piston working therein, said cylinder being provided with exhaust and scavenging'inlet ports adapted to be'ope'ned by the piston at the end of the expansion stroke, and said cylinder being provided witha-mixture inlet port and with a supplementary exhaust port imposition to remain open during the first part of the compression stroke of the piston, a valve for' said supplementary exhaust .port operated by the en'- gine to open saidport during the first part of the compression stroke and to close said port during the latter part of the compres- 'sion stroke and substantially all of the expansion stroke, a valve for the aforesaid mixture inlet port. adapted to open {luring the time of opening of-said supplernhtary exhaust valve, and means for supplying scavengin air and subsequently supplying combustib e mixture to said mixture inlet port when its valve is opened.

i 4.- In an internal combustion engine, the combination of a cylinder, a piston working therein, said cylinder being provided with v an inlet for combustible mixture and for later portion of said stroke.

portion ofthe inward stroke of the piston.

so asto prolong the period of exhaust and to reduce the period of compression so that it is shorter than the per od of expansion, means for supplying scavenging air to said preliminary scavenging inlet portiwhen it is opened by the piston, means for supplying scavenging air to said inlet port for,

combustible mixture and for scavenging air during thefirst part of the inward stroke of the piston and means for supplying combustible mixture to said inlet port during a 5. In an internal combustion engine, the.

vcombination of a cylinder, a piston working therein, said cylinder being provided with spring controlled inlet, means for supplying. to said inlet compressed air for scavengmg and for subsequent-1v supplying to said in et a charge of combustible mixture, said cylinder being also provided with an ex- .4 haust port and with a preliminary scavenging inlet port, both positioned to be opened by the piston substantially at the outer end of its travel, and said cylinder being provided with a supplementary exhaust connection and means for opening the same, during the first part of the inward stroke of the piston and to close such connectlondur- V ing the remainder of suchinward strokeand duringthe outward stroke otthe piston,

6. In an internal combustion eng ne, the

icombination with a cylinder and a pistolrworking therein, said cylinder having ani inlet and provided with an exhaust connection opened when the pistoncompletes its outward stroke, means operated by the env 1' gine for compressing air, a valve controlling communication between saidair compress m means and said lnlet for the cyl1nder,,t0

, abs 1 admit air to the cylinder when the pressure falls therein on'opening the exhaust port, i and a pump operating eriodicallyto re ceive andcompress a de nite charge of air and fuel and force the same into the compressed air passin'g'to the cylinder, after a portion of such compressed air. has passed into the cylinder for scavenging.

7. In an lnternal combustion engine, a

combustion cylinder, a piston working therein, means for'supplying fresh airto.

the cylinder at thebeginning of the comlie pression'stroke a pumpoi. small capacity relatively to said cylinder, 'ineans for sup,

plying a mixture of air and liquid fuel to said pump, said pump having its outletconnected to the fresh air supply means for said cylinder, and said pump being connectedfor operation by said'pis'ton to cause, a mix ture of liquid fuel and air to be compressed therein to sufiicient pressureto vaporize the liquid fuel by the heat of compression and to force the compressed mixture into th fresh air passing to the cylinder,

8. In an internal combustion engine, a.

means operated by the piston in its outward stroke, for compressing a1r,said'a1r conicylinder and a piston worltiinfg' thercin, said cylinder having an exhaust port opened at the end of thewexpansionstroke, means for compressing air at .low pressure, means for :adnntting such compressed air to the said" ycyli iider during the compression stroke, and va'xpump having its outlet connected to the ineans for admlttingair to. said cylinder and having its inlet provided' with means for supplying a mixture of air and liquid fuel,

said pump being of relatively small capacity compare to said cylinder and being conheated for operation by the enginejduring the compression stroke to compress the mix-f ture of air and liquid fuel to suficiently. high pressure to vaporize the fuel by the heat of compression, and to force s'uchcompressed mixture, while still at, high temperature, into the air passing to said cylinder during the compression stroke.

9. An internal combustion engine comprising a cylinder, provided with an exhaust I port and a scavenging inlet port, a, piston opene Whrking in said cylinder and opening said PQPiS at the outerend of the outward stroke,"

pressing means communicating with ysa'id scavenging inlet to blow "coigpressed 'ai'r. throng the inlet when sai ports are the .pisto'n on its inward stroke, and, storage meansconnected thereto to receive and store thc'compressed air till the rendhf the,

next outward stroke, a valve controlling communication between said last named air compressing means and the cylinder, said valve opening'automatically under the'pressure of such air to admit such c oinpressed air to the cylinder when the pressure there in falls on opening of the exhaust valve, and

, air compressingmeans operatedhy spouses I I compressing air said means communicating with saidscavenging inlet port to blow air through the cylinder when said ports are opened, inlet valve means for the engine and air compressing means communicating therewith and operated by the piston on its inward stroke, said valve means being adapted to open automatically when the pressure in the cylinder falls on opening of the exhaust valve, to admit compressed air to the cylinder, means for supplying compressed 7 combustible mixture to the air passing to saidinlet valve means, after a portion of the compressed air has passed therethrou h, and supplementary exhaust connections or thecvlinder, providedwith a valve operated part of/ the instroke to prolong the period of exhaust, while the compressed air is passing ill t0 the cylinder, to scavenge the same, and closedduring the remainder of the' instiolte to permit of compression of the ,c'harge and also closed during the expansion stroke. I

In testimony whereof I have hereunto set my hand, at Los Angeles, California, this 22nd day of June 1914.

" FRANK J. KIMBALL.

-Witnesses C. E. :ALLYN, A. P. Kmcirr th engine and opened during the first 

